This chapter examines the development of a large-scale urban development project launched in the early 2000s: the so-called Science City (Cité des Sciences) in Belval, Luxembourg. The Science City is located in the heart of the Grand Duchy’s former industrial region, between the city of Esch-sur-Alzette and its neighbour municipality Sanem. The development has taken place on the site of a decommissioned steel mill. It now hosts the University of Luxembourg’s main campus as well as a variety of other research institutions. State authorities responsible for the planning and implementation of the Science City purport to comply with (seemingly) innovative sustainable urban planning and design principles, whose guiding concepts derive from related city-university projects across the world. The project is, however, subject to a variety of challenges. Besides meeting the market’s demands for new space, such challenges include the provision of a balanced setting for development beyond economic purposes, the proper integration of the site in the existing built environment, the establishment of a governance structure that reflects the division of powers, functions and users, as well as preventing collisions between the worlds of knowledge production and the old industrial working-class milieus. Belval proved to be innovative for Luxembourg to the extent that the planning ideal of the dense, compact European city was envisaged by means of implementing a large-scale urban project. However, given the associated economic risks, along with the rather traditional planning approach of the institutions involved, path dependence and governance lock-ins may embody persistent challenges to the Science City.